The acoustics I'm talking about here is the most important thing to let a tuner understand all aspects of acoustics, rather than do acoustics, or a master's and a PhD's acoustic paper, so the acoustic theory I speak in this book is practical for people who operate acoustics on the spot.

In 1915, an American named E.S.Pridham set a phone receiver on the horn of a recording sound that could be heard by a group of people celebrating Christmas in San Francisco, and electroacoustics came into being. At the end of the first World War, at the inauguration of President Harding (Harding), the United States Bell Co connected the phone's moving coil listener to the horn of the record phonograph at that time, and was able to transmit the sound to a large group of people watching the inauguration of the president, as a result of which a lot of professional acoustics were produced and opened. There was a study of the sound expansion project. Sound researchers did not simply improve their sound equipment, but also made experiments on various kinds of acoustics to understand human responses to hearing. But the most advanced acoustics researchers all understand that acoustics is an integral part of the study. To understand every aspect of the sound equipment and the human physiological response to the hearing, they have made a great contribution.